Berlin 2018 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 12: Multiferroics and magnetoelectrics II (joint session MA/KFM)

KFM 12.8: Vortrag

Mittwoch, 14. März 2018, 11:30–11:45, EB 202

Reversible Modulation of Magnetic Anisotropy in Pb(Zr_0.2Ti_0.8)O₃ /La_0.8Sr_0.2MnO₃ Multiferroic Heterostructures — •Anil Rajapitamahuni, Lingling Tao, Evgeny Tsymbal, and Xia Hong — Department of Physics and Astronomy,University of Nebraska-Lincoln, Lincoln,NE, 68588

We report a reversible modulation of in-plane magnetic anisotropy energy (MAE) in 4 nm La_0.8Sr_0.2MnO₃ (LSMO) thin films via ferroelectric field effect induced charge doping facilitated by Pb(Zr_0.2Ti_0.8)O₃(PZT) top gate. We employed, planar Hall effect measurements (PHE) to characterize the in-plane magnetic anisotropy in PZT/LSMO heterostructures. The magnetic anisotropy in LSMO is found to be biaxial with easy axes along <110> directions for both polarization states. The extracted biaxial anisotropy fields (H1) from PHE measurements, showed an enhancement in H1 in the accumulation state. Assuming a doping level change of 0.1 electron/Mn due to the polarization switching, the estimated anisotropy energy densities are 0.9 x 10⁵ erg/cm³ and 1.17 x 10⁵ erg/cm³ in the depletion and accumulation states respectively. This corresponds to a 30% enhancement of the MAE in the accumulation state when compared to the depletion state values. First principles density functional theory calculations performed for various Sr doping levels also show an increase in the MAE with an increase in the hole doping, agreeing well with our experimental observations. We attribute this enhancement in MAE to the modification of orbital contribution to spin-orbit coupling via ferroelectric field effect in LSMO.